Thin-film deposition techniques are used to deposit a film of material onto semiconductor substrates for manufacturing integrated circuit devices and optoelectronic devices on the semiconductor substrates.
For instance, Metal-Organic Chemical Vapour Deposition (MOCVD) is a method of depositing a material on a heated substrate, such as a semiconductor wafer. The method comprises a step of introducing precursor gases into a reactor, which has a temperature-controlled environment. The introduced precursor gases are usually directed to a direction, which is perpendicular or is parallel to a major planar surface of the heated substrate. These precursor gases are also introduced close to the major planar surface and close to each other such that the precursor gases chemically react to deposit a material on the major planar surface of the heated substrate, rather depositing on other parts of the reactor.
As an example, the precursor gases include a first precursor gas and a second precursor gas. The first precursor gas includes a Group III element, such as gallium (Ga), while the second precursor gas includes a Group V element, such as nitrogen (N). These precursor gases react to deposit a compound semiconductor, such as GaN, on a planar surface of the heated substrate.
Carrier gases, such as nitrogen (N2) and hydrogen (H2), are also introduced into the reactor to move the precursor gases towards the heated substrate for minimising the deposition of the precursor gases on unwanted areas within the reactor. These carrier gases also act as purging gases for moving these precursor gases out of the reactor.
It is an object of this application to provide an improved apparatus for introducing gases into a reaction chamber for thin-film deposition, in particular for chemical vapour deposition (CVD).